Method and apparatus for forming cuts in catheters, guide wires, and the like

ABSTRACT

A method of forming cuts in elongate objects such as a catheters and guide wires, using a cutting device which includes a movable cutting means, a clamping means for holding the elongate object while the cutting means makes an incision therein, and a manipulating means including a pinch roller assembly including a first roller and a second roller, and configured for advancing the elongated object to the clamping means and rotating the elongate object, the method comprising the steps of: a) providing a length of the elongate object to the manipulating means; b) advancing the elongate object toward the clamping means by rotation of a roller of the pinch roller assembly; c) rotating the pinch roller assembly so as to rotate the elongate object about a lengthwise axis of the elongate object; d) engaging the clamping means around the elongate object; e) cutting the elongate object; f) advancing the cutting means toward the elongate object until a desired cutting depth has been reached; and, g) retracting the cutting means.

This application is a divisional application of U.S. patent applicationSer. No. 08/714,555, filed on Sep. 16, 1996, issued as U.S. Pat. No.6,014,919, on Jan. 18, 2000.

BACKGROUND

1. Field of the Invention

The present invention pertains to making precision cuts in catheters andguide wires. Specifically, a device for holding, advancing, rotating andthen cutting a catheter or guide wire is provided which is able tomanipulate the catheter or guide wire in two degrees of freedom toenable precision control of the location of the cuts. Various clampingmechanisms are provided for manipulating the catheter or guide wire,resulting in controlled variation in mechanical properties.

2. State of the Art

Making cuts in catheters and guide wires requires precision in order toensure reliability because of the medical applications in which they areused. However, it is also important to control costs of production sothat costs to the health care industry can be minimized.

The state of the art is typified by such devices as grinding wires,wound coils, and lasers for making the cuts. But these devices oftensuffer from high cost or imprecise or difficult control mechanisms forproperly positioning both the device to make the cut and the cylindricalobject to be cut.

What is needed is a method and apparatus for making cuts in cathetersand guide wires which allows precise control of characteristics of thecuts. This entails precision holding, advancement and rotation of thegenerally cylindrical object while at least one saw blade is itselfadvanced to make the cut and retracted afterward.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodand apparatus for forming precision cuts in elongate cylindrical objectsincluding catheters and catheter guide wires.

It is another object to provide a method and apparatus for formingprecision cuts by manipulating a cylindrical object in two degrees offreedom to control the parameters of the cuts.

It is yet another object to provide a method and apparatus for holding,advancing and rotating a cylindrical object to be cut.

These and other objects are realized in a preferred embodiment of asystem for making cuts in a catheter, guide wire or other elongatecylindrical object having a lengthwise axis. The system generallycomprises a securing means for repeatedly releasing and then holding theelongate object in a position suitable for cutting it at an angle ortransversely relative to its lengthwise axis, a manipulating means formoving the elongate object so that it can be disposed in the positionsuitable for cutting when it is released by the securing means, and acutting means for forming the at least one precision cut in the elongateobject to any desired depth. The securing means preferably comprises arotatable collet clamp. The manipulating means preferably comprises apinch roller assembly for advancing and holding the elongate object. Thecutting means is preferably a mechanical blade mounted on a rotatablespindle. The clamp is able to hold the object to be cut, as well asposition it by, for example, rotation to thereby expose the entirecircumference of the cylindrical object to the saw blade. By releasingthe clamp, the pinch roller advances the cylindrical object before theclamp is re-engaged to securely hold the cylindrical object for cutting.

The securing means, manipulating means, and cutting means are preferablymounted on a base. The rotating spindle is free to move vertically andhorizontally with respect to the base to thereby control the location,length, depth and angle of the cuts in the cylindrical object disposedadjacent thereto.

Another aspect of the invention is the ability to make precision cuts byproviding means for controlling the rotation and advancement of theobject to be cut and movement of the saw blade spindle member.

Another aspect is the ability to simultaneously make a plurality of cutsin the object. This is accomplished with a saw blade having a pluralityof blades in parallel. Even more cuts can be made by providing more thanone saw blade spindle member, where each is independently movable in twodegrees of freedom.

Another aspect of the invention is to provide more than one spindlemember so that blades can simultaneously make precision cuts atdifferent locations along the length of the cylindrical object.

These and other objects, features, advantages and alternative aspects ofthe present invention will become apparent to those skilled in the artfrom a consideration of the following detailed description taken incombination with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front elevational view of a preferred embodiment made inaccordance with the principles of the present invention.

FIG. 1B is a side elevational view of the invention shown in FIG. 1A.

FIG. 2 is an alternative embodiment of a vertically moving member shownreversed in orientation with respect to FIGS. 1A and 1B.

FIG. 3 is an alternative embodiment of a horizontally moving membershown reversed in orientation with respect to FIGS. 1A and 1B.

FIG. 4A is a front elevational view of an alternative embodiment for theclamping means.

FIG. 4B is a side elevational view of the alternative embodiment for theclamping means of FIG. 4A.

FIG. 4C is a front view which shows that the anvil has a slot.

FIG. 5 is an alternative saw blade assembly which can be used in allembodiments of the present invention.

FIG. 6 is an alternative embodiment which uses two saw blade assembliesto simultaneously make incisions in the catheter.

FIG. 7 is a side view of an alternative embodiment which shows aconfiguration with a base member, a horizontally movable member, and avertically moveable member.

FIG. 8 is another side view of an alternative embodiment which shows aconfiguration of a base member, and a lever arm which moves the cuttingblade in horizontal and vertical directions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made to the drawings in which the various elementsof the present invention will be given numerical designations and inwhich the invention will be discussed so as to enable one skilled in theart to make and use the invention.

The present invention is illustrated in FIGS. 1A and 1B. FIG. 1A is afront view of the preferred embodiment of the invention, and shows thesystem for forming precision cuts in a catheter, a guide wire, or othercylindrical objects. For purposes of keeping in mind the intended use ofthe present invention, a catheter will be referred to as the objectbeing cut, although any cylindrical object can be substituted for thecatheter. However, reference to the catheter is only for the convenienceof writing in terms of a specific cylindrical object, and should not beconsidered a material limitation of the invention. However, referring toa catheter keeps present in mind the objective of having a very precisecutting device, where precision is paramount in most medicalapplications. Furthermore, a catheter is only one embodiment of amedical application, but which easily represents the need for precision.

The system 6 shown in FIGS. 1A and 1B is comprised of several elementsincluding a base member 10 for supporting the structure. Coupled insliding engagement with a vertical base member 12 is a verticallymovable member 14 which has a first vertical coupling face 16 and afirst horizontal coupling face 18. The vertical coupling face 16 isslidingly engaged with a base member vertical coupling face 20.

The mechanism 22 for enabling the sliding engagement between thevertical coupling face 16 and the base member vertical coupling face 20can be any appropriate apparatus. The important consideration is thatthe vertically movable member 14 not be permitted to move horizontally,or the precision of the system will be compromised. Therefore, thetolerances of the mechanism 22 must necessarily be small. A good exampleof an appropriate mechanism 22 is well known to those skilled in the artas a crossed roller bearing slide.

The shape of the vertically movable member 14 is shown here as a smallbackwards “L”. An alternative shape for the vertically movable member 14is shown in FIG. 2. The member 14 is flipped over as compared to theembodiment of FIG. 1A. The important feature of the member 14 is that itprovide two faces 16, 18 which can be slidably engaged to movevertically and provide a second face on which another member canslidably engage to move horizontally.

The system in FIGS. 1A and 1B is also comprised of a horizontallymovable member 24 which has a spindle end 26 and a second horizontalcoupling face 28. This horizontally movable member 24 is slidablyengaged at its second horizontal coupling face 28 to the verticallymovable member 14 at its first horizontal coupling face 18. It should beobserved that the vertically movable member 14 and the horizontallymovable member 24 are capable of moving independently of each other. Inthis way, the system achieves two independent degrees of freedom ofmovement.

The spindle end 26 of the horizontally movable member 24 provides ahorizontal slot 30 in which a spindle 32 is disposed. The slot 30 isgenerally circular to serve as a receptor for the round shaft 34 of thespindle 32. The spindle shaft 34 has disposed on a working end 36thereof at least one circular saw blade 38. The circular saw blade 38 isdisposed vertically on the spindle shaft 34, but may also be angled inother embodiments.

The spindle shaft 34 is coupled to a drive motor by gears, belts, directdrive, or any other appropriate means (not shown) which will cause thespindle shaft 34 to rapidly rotate. The drive motor (not shown) can bedisposed in any appropriate location relative to the spindle shaft. In apreferred embodiment, the spindle shaft 34 is driven by a brushless DCmotor through a toothed timing belt.

The circular saw blade 38 is typical of those found in the art. In apreferred embodiment, the cutting edge 40 of the saw blade 38 is coatedwith industrial diamonds.

The means for holding and otherwise manipulating a catheter 8 to be cutis the clamping member 50. The clamping member 50 is comprised of twomajor assemblies: the clamp 52 and the clamp feeding (supplying) means54, or the device which feeds the catheter 8 to and then through theclamp 52. The clamping member 50 is also coupled to the base member 10and disposed to hold the clamp 52 in a position for easy feeding of thecatheter 8 to the circular saw blade 38.

In the preferred embodiment, the clamp 52 is of the type known to thoseskilled in the art as a collet clamp. A collet clamp is a slottedcylindrical clamp inserted tightly into the tapered interior of a sleeveor chuck on a lathe to hold a cylindrical piece of work. In FIG. 1A, thecylindrical shape of the clamp 52 is visible. It is slotted in that theclamping arms 58 are separate from each other so that they can pull awayfrom the catheter 8 when disengaging, and then securely come togetheraround the catheter 8 when engaging.

In a preferred embodiment, a desirable feature of the clamp 52 is thatit is rotatably mounted within the clamping member 50. The collet clamp52 can then rotate so as to dispose a different portion of the surfaceof the catheter 8 to the saw blades 38. The mechanism for rotating theclamp 52 is shown generally at 56, and is comprised of the clamp 52which is held in a frame which can rotate with respect to the saw blade38.

The clamp feeding (supplying) means 54 seen in FIG. 1B is shown in thispreferred embodiment to be comprised of a pinch roller assembly 60, 62working in conjunction with a feed roller 66. As FIG. 1B should makeclear, the pinch roller assembly 60, 62 feeds the catheter 8 to theclamp 52 by using friction created between two opposing members 60, 66.The upper member is the pinch roller 60. The lower member is the feedroller 66. The feed roller 66 has an axle 68 mounted in the clampfeeding means 54 so that the feed roller 66 can roll. The pinch roller60 is disposed at the end of a lever arm 62 which pivots at a pivotingend 70. Located distally from the pinch roller assembly along the lengthof the lever arm is a hole 72. One end of a spring 64 is insertedtherethrough, and the other end of the spring 64 is coupled at anotherhole 74 to the clamp feeding means 54. The spring 64 provides thetension necessary for the feed roller 64 to push the catheter 8 to theclamp 52.

Having described most of the components in a preferred embodiment of thecatheter cutting assembly 6, the operation of the assembly 6 is asfollows. First, the uncut catheter 8 is placed between the pinch roller60 and the feed roller 66. This can be done by raising the lever arm 62by stretching the spring 64. Releasing the lever arm 62 causes the pinchroller 60 to push down against the feed roller 66, with the catheter 8disposed therebetween. A drive mechanism (not shown) is coupled to thefeed roller 66 to cause it to roll and thereby push the catheter 8toward the clamp 52. The clamp 52 should be in a disengaged position(hole through clamp is larger than diameter of the catheter 8) so thatthe catheter 8 can be fed easily therethrough. After passing through theclamp 52, the catheter 8 is fed sufficiently far past the circular sawblade 38 so that it is in a proper position to have an incision made inor through its surface.

When the catheter 8 is positioned correctly, the clamp 52. is engagedand the saw blade 38 is advanced to make cutting contact. Beforecutting, the saw blade 38 will always be positioned in a retractedposition. The retracted position is both vertically below andhorizontally pulled away from the catheter 8. The first movement of thesaw blade 38 is 1) horizontal advancement toward the catheter 8. This isaccomplished by moving the horizontally movable member 24 relative tothe vertically movable member 14 to which it is attached. Thehorizontally movable member 24 is moved until it has reached the depthof the incision to be made in the catheter 8. The next step 2) comprisesthe vertically movable member 14 moving upwards relative to the base towhich is coupled to thereby make the cut. The saw blade 38 is thenimmediately retracted by moving the vertically movable member 14 awayfrom the catheter 8. The horizontal member is moved only when the nextcut is at a different depth or when all cutting is complete.

If another cut is to be made, the collet clamp 52 is released as step4). The catheter 8 is then fed through the clamp 52 by the feed roller66 as step 5). The collet clamp 52 is then re-engaged in step 6) and, ifnecessary, the collet clamp 52 is rotated to expose a different positionof the catheter 8 to the saw blade 38. The saw blade 38 is then movedhorizontally if the depth of cut is to change, and then vertically tomake the cut and steps 1) through 7) repeat as often as necessary untilall the incisions have been made or the catheter 8 is no longer capableof being grasped by the feed roller 66 and opposing pinch roller 60.

The above description of the operation of the catheter cutting system 6describes the different roles served by the clamp 52. When the circularsaw blade 38 is making a cut in the catheter 8, the clamp 52 holds thecatheter 8 steady. When the cut has been made in the catheter 8, thecatheter 8 is fed through the clamp 52 by causing the clamp to disengagefrom around the catheter 8. After being disengaged, the catheter 8 isfed through the clamp 52 until the next incision point on the catheter 8is in position relative to the saw blade 38. The clamp 52 re-engages soas to be disposed snugly around the catheter 8 to again prevent movementof the catheter 8 during cutting.

It should be recognized from the description above that the width of acut into the catheter 8 is limited to the width of the circular sawblade 38. A wider cut therefore requires that the catheter 8 be advancedslightly past the saw blade 38. However, advancement does not take placewhile making a cut. The saw blade 38 must be withdrawn so that the clamp52 can disengage from around the catheter 8 while it is advanced. Thisis necessary because allowing cutting of the catheter 8 when the clampis disengaged would create an imprecise or useless cut.

Variations of the preferred embodiment are illustrated in FIGS. 4A and4B which show that the clamping means 52 has been modified. As can beseen in FIG. 4A, a stationary support surface 110 is provided with aslot 112 therein for supporting the catheter 8 from below. The slot 112guides and holds the catheter 8 before, during and after cutting.Holding the catheter 8 not only allows more precise cutting, butprevents damage to the catheter 8 which might otherwise occur. A movableclamping member 114 or anvil is also provided to thereby apply force tothe catheter 8 which is clamped between the anvil 114 and the slottedsupport surface 110. FIG. 4B also shows that the anvil 114 has amechanism 116 which allows the anvil 114 to move vertically with respectto the support surface 110. In FIG. 4B the vertical movement mechanism116 is shown as bearings.

FIG. 4C is provided to illustrate an alternative embodiment of the anvil114. As shown, the anvil 114 has a slot 158 which will hold the catheter8 more securely for cutting.

FIG. 5 illustrates a modification to the spindle 32 and saw blade 38arrangement shown in FIGS. 1A and 1B. Specifically, a plurality of sawblades 38 are shown as being mounted in parallel on the same spindle 32.This also means that the saw blades 38 are necessarily coaxial. It isalso preferred that the saw blades 38 have the same diameter so that noindividual saw blade 38 makes a deeper incision in the catheter 8 thanany of the others. However, it should be apparent that if the spindle 32or the saw blades 38 are easily detachable from the system 6, then sawblades of varying diameters might be mounted on the same spindle 32 toachieve a consistent pattern of cuts having different depths.

FIG. 6 is an illustration of another alternative embodiment of thepresent invention. The vertically movable member 14 is shown havinganother shape which enables it to have disposed thereon two horizontallymovable members 24, each having its own associated saw blade or blades38. This embodiment enables the catheter 8 to be simultaneously cut atdifferent circumferentially defined points on the catheter surface. Thisis especially useful in making multiple cuts in catheters, for example,on diametrically opposed positions on the catheter 8.

It should be noted that while the preferred embodiment has been definedas having a horizontally movable member with the spindle for the sawblade coupled thereto, the placement of the vertically and horizontallymovable members can be switched as shown in FIG. 7. In this arrangement,the horizontally movable member 144 is coupled to the base member 142and the vertically movable member 146, and the vertically movable member146 has a spindle 148 rotatably coupled thereto.

In another alternative embodiment of the present invention, shown inFIG. 8, a lever arm 150 is pivotally connected to the base member 154,and is capable of movement in at least two degrees of freedom so that itcan move vertically and horizontally to position a spindle end 152.

Another aspect of the invention which should be clarified is thatrotating the catheter is not limited to using a rotatable clampingmechanism. For example, the clamp can be non-rotatable and disengaged toenable the catheter feeding mechanism to rotate the catheter, and thenre-engage the clamp to make additional incisions. Furthermore, the clampand the catheter feeding mechanism can be rotated together beforeadditional incisions are made.

Alternative aspects of the invention include the substitution of anon-mechanical cutting instrument for the rotating blade of thepresently preferred embodiment. For example, a laser can be provided forcutting through materials which are mounted on the system.

It should also be realized that rotating blades are not the only type ofmechanical blade which can be utilized. Conventional “sawing” blades canalso be provided.

It is to be understood that the above-described embodiments are onlyillustrative of the application of the principles of the presentinvention. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the spiritand scope of the present invention. The appended claims are intended tocover such modifications and arrangements.

What is claimed is:
 1. A method of forming cuts in an elongate object,using a cutting device which includes a movable cutting means, aclamping means for holding the elongate object while the cutting meansmakes an incision therein, and a manipulating means including a pinchroller assembly including a first roller and a second roller, andconfigured for advancing the elongated object to the clamping means androtating the elongate object, the method comprising the steps of: a)providing a length of the elongate object to the manipulating means; b)advancing the elongate object toward the clamping means by rotation of aroller of the pinch roller assembly; c) rotating the pinch rollerassembly so as to rotate the elongate object about a lengthwise axis ofthe elongate object; d) engaging the clamping means around the elongateobject; e) advancing the cutting means toward the elongate object untila desired cutting depth has been reached; f) cutting the elongateobject; and g) retracting the cutting means.
 2. The method as defined inclaim 1 wherein the method comprises the additional steps of: h)disengaging the clamping means from around the elongate object; i)advancing the elongate object through the clamping means; and j)repeating at least the cutting steps e) through g) of claim
 1. 3. Themethod as defined in claim 1 wherein the method comprises the additionalstep of rotating the clamping means with the pinch roller assembly tothereby rotate the elongate object clamped therein and expose adifferent portion of the elongate object to the cutting means.
 4. Themethod as defined in claim 3, wherein the method comprises theadditional step of configuring the clamping means and the pinch rollerassembly to be connected so as to rotate as a unit and thereby rotatethe elongate object clamped therein to expose a different portion of theelongate object to the cutting means.
 5. The method as defined in claim1 wherein the method comprises the additional steps of: h) disengagingthe clamping means; i) rotating the manipulating means to thereby rotatethe elongate object clamped therein to expose a different portion of theelongate object to the cutting means; and j) engaging the clampingmeans.
 6. The method as defined in claim 1, wherein: the clamping meansfor holding the elongate object while the cutting means makes anincision therein more particularly comprises a support surface having aslot, and providing an anvil opposingly moveable against the supportsurface; and the step of engaging the clamping means around the elongateobject more particularly comprises placing the elongate object in theslot on the support surface, and drawing the anvil toward the supportsurface and against the elongate object so as to hold the elongateobject securely against the support surface.
 7. The method as defined inclaim 6, wherein: the step of providing an anvil opposingly moveableagainst the support surface more particularly comprises providing ananvil defining a slot generally opposingly aligned with the slot in thesupport surface; and the step of engaging the clamping means around theelongate object more particularly comprises placing the elongate objectin the slot on the support surface, and drawing the slotted anvil towardthe support surface and against the elongate object such that theelongate object is securely held against the support surface by theanvil in slots defined by the support surface and the anvil.
 8. A methodof cutting an elongate object when using a cutting device which includesa movable cutting means comprising at least one circular saw blade, acollet clamp for holding the elongate object while the at least onecircular saw blade makes an incision therein, and a rotatable pinchroller assembly configured for advancing the elongate object to thecollet clamp and rotating the elongate object, the method comprising thesteps of: a) providing a length of the elongate object to the pinchroller assembly; b) causing the pinch roller assembly to advance theelongate object toward the collet clamp and to rotate the elongatemember about a lengthwise axis so that a desired location to be cut ispresented to the cutting means; c) engaging the collet clamp around theelongate object; d) advancing the cutting means toward the elongateobject; e) cutting the elongate object to a desired depth; and f)retracting the cutting means.
 9. A method of cutting an elongate object,comprising the steps of: a) providing a cutting device including amovable cutting means; b) providing a clamping means for holding theelongate object while the cutting means makes an incision therein; c)providing a manipulating means including a pinch roller assemblyconfigured for rotating the elongate object about a lengthwise axis ofthe elongate member and advancing the elongate object toward theclamping means; d) providing a length of the elongate object to themanipulating means; e) causing the manipulating means to rotate theelongate object and to advance the elongate object toward the clampingmeans so that a portion of the elongate object to be cut is disposed soas to be positioned for cutting by the cutting means; f) engaging theclamping means so as to hold the elongate object immobile for cutting;g) advancing the cutting means toward the elongate object until thecutting means cuts the elongate object to a desired depth; and h)retracting the cutting means away from the elongate object.
 10. Themethod as defined in claim 9, comprising the additional steps of: i)disengaging the clamping means; and j) repeating steps e) through h) ofclaim
 9. 11. The method as defined in claim 9, wherein: the step ofproviding a clamping means for holding the elongate object while thecutting means makes an incision therein more particularly comprises thestep of providing a collet clamp; and the step of engaging the clampingmeans comprises engaging the collet clamp around the elongate object.12. The method as defined in claim 9, wherein the step of providing amanipulating means for advancing the elongate object to the clampingmeans more particularly comprises providing the pinch roller assemblyhaving a pinch roller and a feed roller wherein the pinch roller isbiased toward the feed roller and the pinch roller and the feed rollerare configured to hold the elongate object therebetween, and wherein thefeed roller is controllably rotatable so that the pinch roller assemblyis configured to move the elongate object toward the clamping means adesired amount to position the elongate object for cutting.
 13. Themethod as defined in claim 12, wherein the step of causing themanipulating means to advance the elongate object to the clamping meansmore particularly further comprises controllably driving the feed rollerso as to cause it to rotate, thereby advancing the elongate object sothat a next incision location is positioned relative to the cuttingmeans due to friction against the elongate object due to pinchingbetween the feed roller and the pinch roller.
 14. The method as setforth in claim 9, further comprising the steps of: i) advancing thecutting means horizontally toward the elongate member; and j) cuttingthe elongate member to a desired depth.
 15. The method as set forth inclaim 14, further comprising the step of moving the cutting meansvertically to make a cut in the elongate member after moving the cuttingmeans horizontally.
 16. The method as defined in claim 9, wherein themethod comprises the additional step of rotating the clamping means withthe pinch roller assembly to thereby rotate the elongate object clampedtherein and expose a different portion of the elongate object to thecutting means.
 17. The method as defined in claim 16, wherein the methodcomprises the additional step of configuring the clamping means and themanipulating means to rotate together about the lengthwise axis of theelongate object and thereby rotate the elongate object clamped thereinto expose a different portion of the elongate object to the cuttingmeans.
 18. The method as defined in claim 9 wherein the method comprisesthe additional steps of: i) disengaging the clamping means; j) rotatingthe manipulating means to thereby rotate the elongate object clampedtherein to expose a different portion of the elongate object to thecutting means; and k) engaging the clamping means.
 19. The method asdefined in claim 18, wherein: the step of providing a clamping means forholding the elongate object while the cutting means makes an incisiontherein more particularly comprises the step of providing a colletclamp; and the step of engaging the clamping means around the elongateobject comprises engaging the collet clamp around the elongate object.20. The method as set forth in claim 18, wherein: the step of providinga clamping means for holding the elongate object while the cutting meansmakes an incision therein more particularly comprises providing asupport surface having a slot, and providing an anvil opposinglymoveable against the support surface; and the step of engaging theclamping means around the elongate object more particularly comprisesplacing the elongate object in the slot on the support surface, anddrawing the anvil toward the support surface and against the elongateobject so as to hold the elongate object securely against the supportsurface.